This probe is a high performance polarographic type, which uses pre-loaded Teflon membrane caps and electrolyte fluid. This is the #1 preferred oxygen monitor in the aquaculture industry.

The PINPOINT II Oxygen Monitor™ is affordable, considering its high precision and ruggedness. The PINPOINT II Oxygen Monitor™ comes complete with Membrane caps and electrolyte fluid, probe with 5-foot cable and meter. Extra Membrane Cap/Fluid kits are available, and the 4-meter probe extension cord is an optional accessory.
Given proper care, the PINPOINT II Oxygen Monitor™ should last a lifetime.
Competes with meters in the $700 range.
Powered by a standard 9-volt battery (not included).